The goal of the present study is to examine the development of the infant middle ear using wideband energy reflectance tympanometry. Specifically, this study will examine energy reflectance tympanometry in 1-, 3-, and 6-month-old infants and young adults. Recent studies in adults and older children using reflectance tympanometry have shown this technique to be more sensitive to middle ear disorders than traditional middle ear admittance, as well as being a good predictor of conductive hearing loss. The application of energy reflectance tympanometry in an infant population is of significant interest in light of the current need for a valid test of middle ear function for infants and neonates in newborn hearing screening programs, and subsequent follow up. It is hypothesized that pressure changes in the external ear canal affect the acoustic responses from the infant ear differently than the adult ear. The effects of positive and negative pressure on wideband reflectance patterns in infants will be characterized across age and compared to adult responses. Results of this study will advance our understanding of developmental changes in the infant ear and inform future studies of middle ear dysfunction in infants and neonates. [unreadable] [unreadable]